Discriminating fuze



| c. FlsHER 2,960,029

DISCRIMINATING FuzE 4 Sheets-Sheet 1 Nov. 15, 1960 Filed Jan. 19, 195o v klmN NN w M mm H; N EL;

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wN NN L. C. FISHER Nov. 15, 1960 L `c, FISHER 2,960,029

DISCRIMINATING FUZE Filed Jan. 19, 1950 4 Sheets-Sheet 2 |06 97 :lol loo |08 97 1 |03 74 l IO2+ E: f |07 L e L 'LB loo z IIO l ,75 f L 6 S |05 sa r L. C. FISHER Nov. 15, 1960 l.. c. FISHER DISCRIMINATING FUZE Filed Jan. 19, 1950 4 Sheets-Shed'l 3 FIG. 3.

gmc/m L. C FISHER Nov. 15, 1960 L. C. FISHER DISCRIMINATING FUZE Filed Jan. 19, 1950 FIGA.

97 lll\ IION lllw 90 T 4 Sheets-Sheet 4 3mm/w L. C. FISHER Ww@ This invention relates generally to mine fuzes and more particularly to a fuze `of the extender type for use in a mine adapted to be launched from a plane in flight and to effect the explosion of the mine if it fails to fall within water exceeding a predetermined depth.

Planes are frequently employed to transport mines to enemy waters whereupon the mines are released to be lowered into the water by parachute or directed therein tes 921cm O 2,960,029 Patented Nov. 15, 1960 of this invention will be readily appreciated as the same becomes better understood by reference to the following by a tail fin structure formed for orienting'the mine, dur- I ing its free fall ight through the air, so that the mine strikes the water substantially end lirst thereby to greatly reduce the lshock of impact of the mine with the surface of the water.

It is not uncommon for a mine so launched to fall either on shore or in such shallow water as to be readily detected by the enemy whereupon it may be recovered and dismantled and the control elements thereof analyzed and countermine apparatus therefor taccordingly devised.

It is the object of the present invention to provide a new and improved mine fuze adapted to discriminate between the planting of the mine upon land and in water exceeding a predetermined depth.

Another object is to provide an extender for an underwater ground mine adapted to position within a booster charge a detonator effective when ignited to explode the mine and concurrently therewith to close an electric circuit to a delay mechanism adapted after a predeter- Fig. 1 is a view partly in elevation of the extender fuze mechanism of the present invention as arranged within an underwater ground mine of the type adapted for launching from a plane ying above the surface of the water;

Fig. 2 is a view partly in section of the extender fuze mechanism in an unarmed position;

Fig. 3 is a View partly in elevation and partly in section of the extender fuze mechanism showing the arrangement of the lazy tong assembly and detonator in unarm position; Y

Fig. 4 shows a fragmentary sectional view in elevation of the extender fuze mechanism when submergediwithin water exceeding a preedtermined depth; Y v

Fig. 5 shows an arrangement of the extender fuze mechanism and locking means therefor in position fo firing the mine;

Fig. 6 is al fragmentary section taken along line 6-6 of Fig. 2; and v Fig. 7 is a schematic view of the circuit arrangement of the mine fuze mechanism of the present invention illustrated with respect to the lire control mechanism of the mine. j Referring now to the drawings and more particularly to Fig. l thereof, the extender fuze of the present invention, generally designated by the reference numeral'10, is shown as arranged within an elongated housing'11 therefor secured as by bolts 12 within the end plate 13 of a mine generally designated by the reference numeral 14 of the type adapted for launching from a plane in ight. The arrangement of the extender fuze in the manner indicated provides that the axis thereof is positioned substantially parallel to the axis of the mine for a purpose whichwill become more fully apparent as Y the description proceeds.

mined time to ignite the detonator if the closed circuit has not been opened by hydrostatic pressure by the submergence of the mine within water of a predetermined depth. v

A further object of the invention is to provide a new and `improved extender mechanism adapted to arm a mine released from a plane in ight upon impact of the mine with either land or water and, in case of the former, to effect the destruction of the mine after the lapse of a predetermined interval of time.

A further object is to provide an extender mechanism adapted in response to impact of an airborne mine with either land or water to actuate a delay mechanism effective yafter a predetermined lapse of time to explode the mine if the mine has not reached a predetermined depth of submergence within a body of water.

A still further object is to provide an extender mechanism for use in an airborne mine wherein the detonator is projected into an explosive charge upon impact of the mine with land or water as the case may be, following the release of a mine from a plane in flight, and the ignition of the detonator for firing the charge is effected after a predetermined delay if the mine has not reached a predetermined depth of submergence within la body of water.

A still further object is to provide a new andimprogved exploder mechanism for use in an airborne underwater ground mine adapted to effect the explosion of the mine if raised from a predetermined depth of submergence or to explode the mine if it fails to land in water exceeding this depth of submergence.

I Other objects and many of the attendant advantages Connecting the housing 11 is a substantially U-shaped conduit 15 through which yelectrical connection is made from the electrical component of the extender with the firing control mechanism 17 Fig. 7 of the mine arranged but not shown in the housing 16 and adapted in response to a signal received from a Vpassing vessel to elfect the explosion of the mine. Mine firing control mechanism 11 may be of any type suitable for the purpose such, for example, as that disclosed in the copending application of Albert H. Sellman et al. for Hydrostat Mechanism, Serial No, 432,454, filed February 26, 1942.

The closing plate 13 is secured within the end of the mine casing 18 as by welding thereto at 19 and having secured to the outer periphery thereof as by bolts 21 a disc shaped cover 22 to which the tail assembly generally designated 23 may be fastened as by a mulitplicity of brackets 24 suitably secured as by welding thereto at 25. Openings of any suitable number or size may be provided about the side wall of the cover as at 26 whereby pressure from the surrounding water may be communicated to. the hydrostatically controlled mechanism of the extender and further to provide admission of cable 27 whereby the arming pin 2S of the fuze is withdrawn therefrom as the mine is launched.

Secured in any suitable manner within the side wall of the mine casing is an attaching plate 29 having therein eye-equipped brackets 31 by which the mine is secured to the release mechanism of the transporting plane.

Preferably cast within the mine about the various con trol elements therefor is an explosive charge 35 admitted to the mine through the nose portion 36 thereof, now' shown closed as by the cappiece 3'7. The explosive 35 is4 eifective when ignited either by means of the operation of the extender mechanism of the present invention, as will be herein disclosed or by means of the lire control mechanism 17 of the mine arranged within the housing 16 and adapted to explode the mine in response to a signal received by an enemy Vessel.

As shown in Figs. 2 and 3, the extender of the present invention is comprised of a chassis member 40 having thereon a ange section 41 wherein is provided diametrically arranged apertures 42 through which bolts may be inserted for securing the fuze within the end plate of the mine as illustrated in Fig. 1. Gaskets formed from rubber or any other suitable material may be pro-vided between the [flange 41 of the chassis and that of the fuze housing 11 and end plate 13 of the mine whereby a pressure and water-proof seal therebetween may be established as the attaching bolts 12 for the extender fuze are tightened.

Extending upwardly from the ilange section 41 of the chassis and preferably formed integral therewith is a cylindrical wall section 43 whereby is provided in the chassis a well or recess 44 shownfelosed as by a cappiece 45 secured thereover by bolts 46 extending through projecting ears 47, Fig. 3, formed in the outer periphery of the cap to threadedly connect with vertically disposed ribs 48 arranged about the periphery of the wall section 43.

Rising vertically from the surface of the cappiece 45 is a tubular extension or riser 49 wherein is provided a plurality of radially arranged bores 50. Retained Within these respective bores are balls 51 formed preferably from steel and movable inwardly therein responsive to engagement with the outer surface of the balls of a cam surface 52 provided `as an inner `chamber in the open end of an arming cap 53 adapted for telescoping over the extension 49 to thereafter be secured thereto as by the arming pin 28. The pin is so arranged as to extend through aligned bores, not shown, provided therefor in the extension and cap members 49 and 53 respectively.

The balls 51, when forced inwardly by the cam surface 52 of the cap as the latter is inserted over the extension 49, are eifective to engage an annular groove 55 formed in a locking member 56 secured as by threading to the reduced end of a plunger on shaft section 57 thereby to secure the plunger to the chassis against movement with respect thereto during such time as the arming cap 53 is in safe position over the extension, as illustrated in Fig. 2. The pin 28 further secures the plunger 57 with the chassis against accidental or premature movement with respect thereto by engaging a second annular groove formed in the locking member as at 60.

The releasing of the plunger 57 is accomplished by the withdrawal of the pin 28 from the fuze by the cable 27 as the mine falls f-ree of the plane, as heretofore described, thereby allowing the cap 53 to be accelerated free of the balls 51 by a helical spring 61 arranged about the cap and initially compressed between the cappiece 45 and an Iannular flange portion 62 formed about the outer portion of the cap 53, as illustrated in Fig. 2, to allow the balls 51 to fall free of their engagement with groove 55. The release of the plunger 57 in the manner indicated yallows the plunger to move inwardly with respect to the fuze chassis either in response to inertia shock `as may be 'received by impact of the mine with either land or water, or by hydrostatic pressure as applied to the outer surface of a diaphragm member 63 secured as by clamping to a shoulder 30 of the plunger 57 by Washers 64 and 65 drawn to the shoulder by a nut 66 threaded with the shaft as lat 67.

The diaphragm 63 may be formed from any suitable material such, for example, as rubber or the like, and secured about its periphery to the base of the recess 44 as by an annular ring member 67 threaded within the wall section 43 of the chassis as at 68 and having therein diametr'ically arranged slots 69 whereby a Spanner wrench or like tool may be inserted for rotation of the ring into clamping engagement with the outer surface of the diaphragm. Ports 70 provided in the side wall of the tubular section 43 admit pressure from the surrounding atmosphere or water, as the case may be, to the outer surface of the diaphragm whereby the plunger secured thereto is caused to move inwardly as pressure against the outer surface of the diaphragm is increased to a predetermined value. Movement inwardly of the plunger 57, after the release thereof by disengagement therewith of pin 28 and the locking balls 51, is limited by the depth of a well 71 arranged in the chassis beneath the diaphragm 63 and within which washer 65 is received.

Secured to the inner surface of the chassis as by screws 73 is a substantially U-shaped guide member 74. Vertically arranged slots 75 provided in the guide are adapted to receive sections 76 of an extender member 78, Fig. 6, operatively connected to the plunger 57 as by a lazytong assembly generally designated -80 and adapted to amplify movement of the plunger to extend an electroresponsive detonator 81 into operative relationship with abooster charge 82 secured to the closed end of the guide member 74 as by threaded member 83 preferably furnace brazed to the latter.

The extender member 78 is provided with an axial bore 84 threaded for receiving therein the threaded end portion 85, Fig. 3, of the detonator 81. Arranged for intersecting bore 84 in a lateral bore 86 through which leads 87 of the detonator extend to connect with a terminal plate 88 after having passed through the slot 75, Fig. 6, of the guide 74. The detonator when in the extended position, as indicated in Figs. 4 and 5 is effective, when ignited by current supplied thereto through a circuit arrangement as shown in Fig. 7, to ignite the booster charge 82 and thereby to cause the explosion of the mine as will become more apparent as the description proceeds.

The arm sections 90 of the lazy-tong `assembly 80 are pivotally secured within bifurcated portions 92 of the chassis as by pins 93, the arms having therein elongated slots 94 wherein is received a pin 95 adapted to operatively connect the arms with a bifurcated portion 96 of the plunger whereby movement of the latter is effective to extend the tongs for projecting the detonator unit 81 outwardly from the base end portion of the bracket in the manner heretofore described.

A pair of springs 97, initially extended between the ends of the arms 90 and projecting ears 98 struck up from the closed or bight end of the U-guide 74, are eiective to initially maintain the tong assembly 80 in a retracted position, as illustrated in Fig. 3, until force of a predetermined value is applied to the plunger 57 to cause inward movement thereof.

Secured to the outer face of guide 74 as by screws 100 is a detent or latch assembly generally designated 101 and including a laterally movable plunger 102 initially maintained in a retracted position by a flange 103 forming a part of bracket 104 also secured to the outer face of the guide 74 as by screws 105. The plunger 102 has secured thereto as 'by set screw 108 an annular ring section 106 against which a helical spring 107 is compressed for u-rging the plunger to an extended or locked position, Fig. 4, as it passes beneath the lower edge of the flange 103 upon inward movemnet of the plunger 57.

By reason of the arrangement of the plunger 57 in parallel alignment with the axis of the mine 14 the plunger is caused upon impact of the mine with either land or water, as the case may be, to be driven inwardly into the fuze to the position indicated in Fig. 4 whereupon the detonator 81, carried thereby, is placed in operative relationship to the booster charge 82 as the plunger 102 of the latch moves beneath ange 103.

The plunger 102 of the latch when in extended position, Fig. 4, is Iadapted to engage an actuating arm `109 o f an electrical switch 110 of a type suitable for the purpose,such for'eiiample as amicroswitch, and secured as by screws '111 to an extension of the plate 104 as indicated in Fig. 2. 'Ihe switch when so engaged by plunger 102 is effective to close an electric circuit from a battery 1'12, Fig. 7, through a delay control mechanism generally designated 1 13 and including a heating coil `14 so disposed with respect to a thermal responsive element 1:15 that when `the element is sufficiently heated by the coil lit is caused to bend into engagement with a contact member 116 and thereby close a circuit from battery 112` through the detonator 81 to effect the explosion of the mine, or render the mine so inoperative as to be of little value if recovered by the enemy.

If, however, during the interval of the heating of the element 115, pressure of a predetermined value is applied to the outer surface of the diaphragm 63 as may be caused by the sinking of the mine :withn Water exceeding a selected depth, the plunger 102 of the latch, now resting against the lower surface of the flange section 103, Fig. 4, is caused, by a still further extended movement of the member 78, to be shifted to the posit-ion indicated in Fig. 5, in which position the switch actuating member 109 is released sufficiently to open the switch and disconnect battery 112 from the element y114, thereby to allow strip 115 to cool before contact is made between element 115 and the contact 1116 to fire the mine. The interrupting of the fuze firing circuit in this manner Aallows the control mechanism 17 of the mine to assume its usual function in controlling firing of the mine in response to the influence of a vessel passing in the vicinity thereof.

If, for any reason, prior to the firing of the mine by influence of a passing vessel, the mine is withdrawn from the water as may Abe done by the enemy in an attempt to recover the mine, the resultant outward movement of the plunger 57 responsive to the reduction in pressure against the surface of th-e diaphragm 63: carries the plunger 102 Aof the latch again into .operative relationship with the switch 110 whereupon the mine is fired after the lapse of the time delay Ias established by the mechanism 1131as heretofore described.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that Within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the paymen-t of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A fuze for an underwater ground mine adapted to 'be released from a plane in flight including, in combination, a housing, a booster charge arranged in said housing and adapted when ignited to explode said mine, 'an electrorespousive detonator adapted when energized to ign-ite said charge, said detonator initially being disposed in safe position and movable into operative igniting relationship with respect to said charge upon impact of the mine with either land or Water, an initially open electric circuit for energizing said detonator, a normally open time delay thermo switch for closing said electric circuit as said switch is actuated to a `closed position at the termination of -a predetermined interval `of time measured thereby, heater means for actuating said thermo switch to said closed position, means responsive to said impact for actuating said heater means, and hydrostatic means for interrupting the operation of said heater means prior to the closing of said circuit when the mine submerges to a predetermined depth within a body of water.

2. A uze for an underwater ground mine adapted to be released from a plane in flight including in combination a housing, a booster charge arranged in said housing `and-effective Awhen ignitedy to explode said mine, means for igniting said charge including an electroresponsive detonator movable from a safe to operative relationship with said charge upon impact of the mine with either land or water, a power source, an initially open circuit for energizing said detonator from said source to effect the ignition of said charge, an electroresponsive element adapted when energized to emanate heat therefrom, a second circuit for energizing said element from said source when the second circuit is closed, a switch connected to close said second circuit as said detonator is moved into operative relationship with said charge, a delay mechanism interposed in said first circuit aud having a part thereof movable to close said first circuit in response to heat received from said element, and hydrostatic means responsive to pressure, of the surrounding water for opening the second circuit when the mine sinks to a predetermined depth Within a body of Water.

3. A fuze for an underwater ground mine adapted to be released from a plane in flight including, in combination, a housing, a booster charge arranged in said housing and effective when ignited to explode said mine, means for igniting said charge including an electrorespionsive ydetonator movable from -a safe position into 'operative relationship with said 'charge upon impact of the mine with either land or water, an electroresponsive heater, ta circuit for applying current to said heater, a switch operative concurrently with movement of said detonator into operative relationship with said charge to cl'ose said circuit to said heater, a thermal element arranged in adjacency to said heater and movable in response to heat received thereby, a circuit for energizing said detonator and arranged to be closed by said thermal element upon predetermined movement thereof, and means for interrupting said heater circuit as the mine submerges to a selected depth within a body `of water.

4. A fuze for an underwater ground mine adapted to be released from a plane in flight including, in combination, a housing, van inertia responsive element movable in said housing to an armed position responsive to the impact of the mine with either land or water, a booster charge arranged in said housing and adapted when ignited to effect the explosion of said mine, an electroresponsive detonator movable by said element from a safe position into operative relation with respect to said charge, means for energizing said detonator to effect the ignition of said charge and including lan initially open electric circuit, a power source arranged in said circuit, a normally open delay thermo switch for closing said circuit as the switch is actuated to a closed position after a predetermined time delay measured thereby, a heating element for actuating said thermo switch to said closed position, means responsive to movement of said inertia element into said armed position for actuating said heating element, and means responsive to a predetermined hydrostatic pressure for interrupting the operation of said heating element prior to the lapse of said time delay.

5. In an aircraft planted marine mine, the combination of an electroresponsive detonator, a switch, a booster charge, extender means including an inertia responsive plunger having means thereon for simultaneously closing said switch and moving said detonator into operative tiring relation with respect to said charge as the plunger is moved to an extended position in response to impact of the mine with either lland or water, a source of power, a thermo actuated time delay device arranged to be set in operation by a predetermined amount of heat as the switch closes and to operatively connect said detonator to said source at the termination of a predetermined interval of time measured by the thermo actuated time delay device, means responsive to a predetermined pressure of the surrounding water for moving said plunger to a further extended position, said switch actuating means on the plunger being arranged thereon to open said switch as the plunger moves to said further extended position and to again close the switch as the plunger re'- turns to said first extended position when the pressure of the Water is reduced below said predetermined Value, and a mine ring control mechanism for energizing said detonator from said source in response to the inuence of a vessel in the vicinity of the mine while the plunger is in said further extended position.

References Cited in the file of this patent l UNITED STATES PATENTS Minkler Feb. 15, 1921 Hammond Nov. 26, 1946 FOREIGN PATENTS Great Britain Feb. 13, 1933 Italy Dec. 4, 1939 

